Petroleum and Natural Gas Fields in Wyoming Page: 83

REVIEW OF OIL AND GAS FIELDS

lel and about 2 miles apart, trend northwest
and southeast. The southwest flank of the
Crooks Gap structure dips sharply, reaching
75, and the northeast flank dips about 300.
The total closure at Crooks. Gap is about 3,000
feet, and the productive closure is about 400
feet. Steele shale is exposed on the surface at
an elevation of about 7,000 feet.
As early as 1925 a well was drilled on the
Crooks Gap structure that reportedly produced
40 barrels of oil a day from the Frontier for-
mation. It was not until 1944, however, that
commercial oil production was realized. The
discovery well was completed in the NW1/
sec. 18, with an initial daily production of
1,478 barrels from the Lakota sandstone at
5,275 feet. In 1947 oil was discovered in the
Muddy sand. Subsequently, two wells were
dually completed in the Muddy and Lakota
formations. Oil was found in the Fourth
Frontier sand in February 1956 and in the
Nugget sand in May 1956. To January 1957,
eight wells had been completed in the Lakota
formation, two in the Muddy sand, one in the
Fourth Frontier sand, and two in the Nugget
sand. Two of the Lakota wells were aban-
doned by January 1957.
During January 1957 a daily average of
1,546 barrels of oil was produced at the field.
The log of a well drilled in the NE1/4NE1/4
sec. 13 showed the depth, in feet, to the for-
mation top as follows: Frontier, 3,875; Muddy,
5,175; Lakota, 5,333; Morrison, 5,477; Sun-
dance, 5,733; Nugget, 5,922; and Phosphoria,
8,003. Analyses of oil from the Muddy and
Lakota sands, gas from the Lakota sand, and
water from the Second Frontier, Cloverly and
Tensleep formations are given on pages 364 and
365 and in tables 8 and 9 (pp. 288 and 294,
respectively).
On December 31, 1956, there were 9 active
oil wells and 10 abandoned wells in the field.
Production during 1956 was 638,349 barrels
of oil and 31 million cubic feet of gas. Cumu-
lative production to the end of 1956 amounted
to 7,663,401 barrels of oil and 743 million cubic
feet of gas.
An unusual operating feature is transpor-
tation of gas from one of the Muddy-sand
wells to the Lost Soldier field through the oil
pipeline. The gas is injected into the oil line
at Crooks Gap and removed by means of large
gas-oil separators at the Lost Soldier field.
The oil is transported to the refinery at Sin-
clair, Wyo., through the Big Sand Draw-Sin-
clair pipeline.
A unit agreement for the field was approved
by the Acting Secretary of the Interior on
October 15, 1937.

CRYSTAL CREEK
Crystal Creek anticline in W1/2, T. 54 N.,
R. 93 W., Big Horn County, is an asym-
metrical antichne with a curved axis; it in-
cludes two structural highs, one at the inter-
section of secs. 5, 6, i, and 8, and the other
in the NW1/4 sec. 19. The Chugwater forma-
tion is exposed on the anticline at an elevation
range of 4,000 to 4,300 feet. A persistent bed
in the Sundance formation outlining both
highs dips about 350 on the west side of the
structure and about 10 on the east side. The
total closure of the structure is about 800 feet.
A well drilled in 1919 in the NW1/4NWl/4
sec. 8 produced 5 barrels of 24 API gravity
black oil daily from a sand at 963 to 983 feet.
Several unproductive wells were drilled on
both the north and south highs. The only well
that has shown commercial possibilities was
drilled in 1948 in the NWANW1/4NW1/4 sec.
8. The well had an initial daily production of
20 barrels of 190 API gravity oil from the
Tensleep sandstone at 964 to 997 feet. The
log of the well shows the Dinwoody at 655
feet, the Embar limestone at 715 feet, and the
Tensleep at 964 feet. Analysis of a stored
sample of the oil is given on page 365. Anal-
ysis of water from the Embar and Tensleep
formations are given in table 9 (p. 293). The
greatest depth reached was 1,805 feet in a
well in the SW1/4SW1/4 sec. 5. The Ten-
sleep, Amsden, and Madison formations were
tested, but neither oil nor gas was found in
commercial quantities.
Only 76 barrels of oil has been reported pro-
duced from Crystal Creek. In November 1956
there were two oil wells in the field, and both
were shut in.
DALLAS DOME
The Dallas Dome (Popo Agie in early re-
ports) oilfield (fig. 53) in sec. 13 and sec. 24,
T. 32 N., R. 99 W., Fremont County, is on a
small anticlinal structure on a major line of
folding (formerly referred to as the Shoshone
anticline) parallel to the Wind River Moun-
tains. It is separated from Derby Dome field
to the southeast by a shallow syncline and
from Lander field to the northwest by a much
deeper syncline. The Dallas Dome structure
has at least 300 feet of independent closure.
The outcropping limestone near the crest of
the structure dips 100 to 180. The Chugwater
formation is exposed on the surface at an
average elevation of 5,410 feet. The Little
Popo Agie River cuts through the center of
the structure.

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